Assigxor of oxe-half



(No Model.)

C. BROWN.

ARTIFICIAL SLAIE.

Patented Mar. 12, 1889.

"I MII-11mm@ Un vena/r:

Unrrnb STATES Partnr OFFICE.

CALVIN BROIVN,

OF SAN FRANCISCO, CALIFORNIA, ASSIGOR OF ONE-HALE TO JOHN II. MILLER, OESAME PLACE.

ARTIFICIAL SLATE.

SPECIFICATION forming part of Letters Eatent No. 399,374, dated March12, 1889.

Application filed January '7, 1888. Serial No. 260,032. (No modehl Toall trzomy if may concern:

Be it known that I, (.YALVIN BROWN, a citizen of the Ifnited States,residing at the city of San Francisco, county of San Francisco, and

5 State of California, have invented a new and useful article ofmanufacture-to wit, an Artiiicial Slate-#of which the following is afull, clear, and exact; description.

My invention relates to improvements in 1o rooting and sheathingbuildings and other product-ion of a slate or slab with such aninstructures; and the object thereof is to obtain an artificial. slateof durable and incombustible quality to take the place of and be usedfor the same purposes as natural slate; and 15 it consists in making,forming, and molding such artificial slate, and in the product soproduced and in the peculiar form and configuration of the slabs orstrips thereof, as will be hereinafter more particularly explained. Iattain these objects by the manufacture of the slate or stripsillustrated in the aecompanying drawings, in which- Figure 1 is a planshowing an under side view of a slate with a part of its interstitialweb projecting beyond the plastic material forming the body of theslate. Fig. is avertical longitudinal section of a slate, showing i theweb whollyinclosed by thebody material.

Si m ilar letters refer to similar parts throughi l the slate being`held in position thereby, and

out the several views.

A an interstitial web. It maybe formed of wire, but preferably, onaccount of its superior stiffness, of expanded metal or slashed metallicscreening, made according` to the specification of United States LettersPatent No. 297,382, granted to John F. Golding on April 22, 1884. Theweb is of thesame or nearly of thc same lateral dimensions as the slate.

The body material I3 3 may be of any impervious, durable, andineombustible substance susceptible of being made plastic, and in thiscondition worked around and through the interstitial web, afterwardbecoming hard 45 and indestructible and adhering closely thereto. Theseconditions are fulfilled bythe use of the best qualities of Portlandcement; but it is evident that any mastic of suitable materials properlyprepared may be used for the I thus prevented from slipping down uponslop- 5o terstiti al web.

The slate may be of uniform thickness; but for roofing purposes it isbetter that it should be made thicker at the butt, diminishing graduallyto the opposite end, where it can be molded of any desirable thickness,even down to the point of the vinterstitial web, or the web itself mayproject beyond the body material, as shown in Fig. 1.

On the under side of the slate grooves g g 6o are formed, the same beingcaused by and left from the molding operation by which the slate isformed, and may be availed of in laying the slate in place upon theroof, as hereinafter mentioned. The slate is molded in an open frame ormold, across which laterally are placed rod-supports for the sheet ofinterstitial web, by which means the web is raised above the molding-bedon which the frame rests, and thus admits of the plastic body material,when fitted into the mold, being distributed through and below the web.After the plastic material is consolidated into the mold by tramping orby pressure and the perfectly-formed slate is removed therefrom thegrooves remain, so that afterward when the slate is to be laid in placethese grooves may be placed over rods adjusted upon the roof,

So ing surfaces. The plastic material after the slate is formed beingtruly surfaced and slicked offen the upper or weather side, the underside being made plain and smooth by the molding-table upon which it ispressed, it is 8 5 left for a short time to set, when the moldingframeis removed, the slate being then placed aside for further indurationuntil it is fit for use. In this manner it is evident that slabs orstrips of any desirable dimensions of the 9o combined body material andiutersti tial web may be made.

In order that nails or screws may be used for fastenin the slate orslabs in place, holes may be pierced in the same at the time of 95molding them or afterward, as may be desired.

I am aware that slabs of artificial stone have heretofore been made ofplastic material in molds to be used for various purposes; but none ofsuch has ever been Amade having the interstitial Web hereinabovedescribed, nor to be used for roofing or sheathing as natural slate.

Having vthus fully descr'ibed myinvention, I claim as new and desire tosecure by Letters Patentfl. As a new article of manufacture, an articalslate consisting of an interstitial Inetallic web and a coveringr of setplastic n1aterial, as set forth. t. Y

2. As a new article of manufacture.. an artiiicial slate consisting ofan interstitial metallic web and coverings of set plastic material onboth sides tapered from one end to the other, as set forth.

3. As a new article of manufacture, an artificial slate consisting of aninterstitial metallic web and a covering of set plastic material on bothsides, one side having transverse grooves therein, as set forth.

v CALVIN BROVN. lVitnesses:

11W. EAsTMAN, J. P. LANGHORNE.

